Electron gun electrode holder

ABSTRACT

An electron gun electrode holder supported by insulating support members disposed within the neck of a cathode-ray tube and supporting the electrode of an electron gun within said neck, which electrode holder has its and portions secured to the associated insulating support members and provided with projections to prevent its relative axial displacement relative to said insulating support members, thus preventing its loosening in direction both parallel and perpendicular to the tube axis to prevent the electron gun electrodes from getting out of alignment with one another so as to prevent degradation of the reproduced picture quality.

United States Patent Nagao, deceased ELECTRON GUN ELECTRODE HOLDER Tomohiro Nagao, deceased, late of Yokohama, Japan by lwao Nagao, executor Assignee: Hitachi Ltd., Tokyo, Japan Filed: Dec. 29, 1971 Appl. No.: 213,657

Inventor:

Foreign Application Priority Data i A Dec. 30, 1970 Japan ..45/137259 US. Cl. 313/256, 313/82, 313/70 C, 313/85 S Int. Cl H01j 1/88, HOlj 11/42 Field of Search 313/85 S, 70 C, 256, 313/82 References Cited UNITED STATES PATENTS 6/1968 Andrews 313/70 C 4/1971 Blumenberg 313/70 C 9/ 1971 Marks et al. 313/70 C Nov. 13, 1973 Primary Examiner-Rudolph V. Rolinec Assistant Examiner-Saxfield Chatmon, Jr.

Attorney-Craig et al.

[57] ABSTRACT An electron gun electrode holder supported by insulating support members disposed within the neck of a cathode-ray tube and supporting the electrode of an electron gun within said neck, which electrode holder has its ancl po rti o ns secured to the associated insulating support members and provided with projections to prevent its relative axial displacement relative to said insulating support members, thus preventing its loosening in direction both parallel and perpendicular to the tube axis to prevent the electron gun electrodes from getting out of alignment with one another so as to prevent degradation of the reproduced picture quality.

4 Claims, 3 Drawing Figures PATENTEUNUV 13 I973 FIG.2

FIG.

FIG.3

ELECTRON GUN ELECTRODE HOLDER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electron gun electrode holders to support the electrode of electron guns for cathode-ray tubes.

2. Description of the Prior Art The electron gun electrode holder for cathode-ray tubes is usually supportedby insulating supports (hereinafter referred to as insulating support rods) disposed within the neck of the tube envelope and supports the electrode of an electron gun. In the usual electron gun electrode holder, its end portions fitted in and secured to respective insulating support rods are planar, so that the junctures between the electron gun electrode holder and insulating support rods poorly resists forces in the direction parallel to the plane of the planar end portion, that is, in the direction parallel to the tube axis. Therefore, it is possible that the electrodes accidentally get out of alignment resulting in deterioration of the picture quality.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view showing the construction of the neck of a color picture tube.

FIG. 2 is a perspective view showing a prior-art electron gun electrode support.

FIG. 3 is a perspective view showing an embodiment of the electron gun electrode support according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although the following description is concerned with a three-electron-gun type color picture tube as an example of cathode-ray tubes to which the electron gun electrode holder according to the invention is applied, it is to be understood that the invention can also be applied to single electron gun type cathode-ray tubes.

To facilitate the understanding of the invention, a prior-art electron gun electrode holder will first be described with reference to FIGS. 1 and 2.

FIG. 1 shows the construction of the neck of a threeelectron-gun type color picture tube. Reference numeral l designates a glass tube envelope neck, within which extend three insulating support rods 2a, 2b and 2c in a triangular arrangement. Three electron gun electrode holders 3a, 3b and 3c are secured between adjacent ones of the three insulating support rods 2a, 2b and 2c. The electron gun electrode supports 3a, 3b and 3c carry respective cylindrical electrodes 7a, 7b and 70 secured to their arcuated central portion 4.

Thus, a plurality of electrodes secured to their respective holders and extending substantially parallel to the tube axis constitute an electron gun structure.

trode holder 3a is formed by working an elongate strip with a press mold. It has a substantially arcuated central portion 4 with radius of curvature corresponding to the outer diameter of the aforesaid electrode. lts arm portions 4a on opposite sides of the arcuated portion 4 extend radially from the arcuated portion, and they are bent to form end portions 5. The end portions 5 are hitted in and secured to the respective insulating support rods 2a and 20, as shown in FIG. 1, so that the holder 3a is fixed in position. Since three electron gun electrode holders are arranged within the tube neck, the opposite end portions 5 of each holder 30 are arranged such that their extensions make an angle of substantially degrees. With a single electron gun tube, this angle is about degrees. The end portions 5 of each electron gun electrode holder respectively have several end extensions 6 in order to increase the strength of their bond with respect to the associated insulating support rods (FIG. 1).

The individual electron gun electrode holders of the 'above structure carry respective electrodes fitted in their central circular portion and secured thereto by a suitable means such as welding and have their respective end portions secured to the insulating support rods to constitute an electron gun structure.

With the'above construction of the electron gun electrode holder, however, the juncture between its end portion, which is planar, and the associated insulating support rod poorly resists forces in the direction parallel to the plane of the planer end direction parallel to the plane of the planar end portion, that is, in the direction parallel to the tube axis. Therefore, the electrodes constituting the electron gun structure are likely to get out of alignment, resulting in deterioration of the picture quality.

The invention is intended to obviate the above drawback, and it features an excellent electron gun electrode holder provided with projections extending from and at substantially right angles with respect to the end portions. It will now be described with reference to FIG. 3.

FIG. 3 shows an electron gun electrode holder for color picture tubes embodying the invention.

In the Figure, the same ports as those in FIG. 2 are designated by like reference numerals. The embodiment of FIG. 3 differs from the holder of FIG. 2 in the provision of planar projections 8a and 8b extending from opposite sides of and at substantially right angles with respect to each of the end portions 5. With this structure of the electron gun electrode holder 9, it is secured to the insulating support rods- (FIG. 1) by means of the end portion 5 and its opposite side projections 8a and 8b. Thus, the loosening of the holder 9 in the direction of tube axis is prevented by the planar projections 8a and 8b, while its loosening in the peripheral direction about the tube axisv is prevented by the end portion 5.

While in the above embodiment two planar projections 8a and 8b are provided to extend from opposite edges of each end portion 5, similar effects may also be obtained by the provision of either one of the projections 8a or 8b alone.

As has been described, the electron gun electrode support according to the invention has end portions which are to be fitted in the associated insulating support rods and each of which consists of a portion extending parallel to the tube axis and at least one projection extending from the edge of said parallel portion and substantially parpendicular to the tube axis, the juncture between the holder and insulating support rod will not become loose when it experiences vibratory shocks or forces in the direction parallel or parpendicular to the tube axis. Thus, there will be no possibility that the electrodes get out of alignment due to accidential shock, thus ensuring a clear picture. Also, since according to the invention the mechanical strength of the juncture between the electron gun electrode holder and insulating support rod is increased, the axial dimension of the tube can be reduced compared to the tubes using the conventional electron gun electrode holder.

What is claimed is:

1. An electron gun electrode holder comprising an elongate strip having opposite ends thereof fitted in and secured to respective insulating supports disposed within the neck of a cathode-ray tube and an arcuated central portion supporting a cylindrical electrode of an electron gun, said arcuated central portion having a radius of curvature corresponding to the outer diameter of said cylindrical electrode, and said opposite ends of said elongate strip consisting of radial portions extending from the opposite ends of and radially with respect to said arcuated central portion, end portions extending from said respective radial portions in planes parallel to the axis of said tube, and at least one projection extending from either one of the opposite side edges of each of said end portions and in a plane substantially at right angles with respect to the axis of said tube.

2. An electron gun electrode holder as defined in claim 1, wherein said end portions with said projections are embedded in said respective insulating supports.

3. An electron gun electrode holder as defined in claim 2, wherein said projection on each of said end portions lies in a plane substantially at right angles to the plane of the radial portion from which the adjacent end portion extend.

4. An electron gun electrode holder as defined in claim 1, wherein the edges of said arcuate portion of said elongate strip are disposed in respective planes transverse to said tube axis. 

1. An electron gun electrode holder comprising an elongate strip having opposite ends thereof fitted in and secured to respective insulating supports disposed within the neck of a cathode-ray tube and an arcuated central portion supporting a cylindrical electrode of an electron gun, said arcuated central portion having a radius of curvature corresponding to the outer diameter of said cylindrical electrode, and said opposite ends of said elongate strip consisting of radial portions extending from the opposite ends of and radially with respect to said arcuated central portion, end portions extending from said respective radial portions in planes parallel to the axis of said tube, and at least one projection extending from either one of the opposite side edges of each of said end portions and in a plane substantially at right angles with respect to the axis of said tube.
 2. An electron gun electrode holder as defined in claim 1, wherein said end portions with said projections are embedded in said respective insulating supports.
 3. An electron gun electrode holder as defined in claim 2, wherein said projection on each of said end portions lies in a plane substantially at right angles to the plane of the radial portion from which the adjacent end portion extend.
 4. An electron gun electrode holder as defined in claim 1, wherein the edges of said arcuate portion of said elongate strip are disposed in respective planes transverse to said tube axis. 